Results
author = "Oliveira, F."
Nano-meter size WC whiskers grown over a compacted pellet of praphite: tungsten powder mixture heated with an ultra-fast heating rate by a concentrated solar beam
Author(s) :
Dias, Susana
,
Oliveira, F. A. Costa
,
Granier, Bernard
,
Badie, Jean Marie
,
Fernandes, Jorge Cruz
,
Rosa, Luís Guerra
Description :
In equilibrium binary W-C system, mono-carbide WC is acknowledged as the stable phase under presence of excess free carbon up to temperature 2700 C whereas sub-carbideW2C would form between 1250 C and 2700 C under the carbon-deficiency condition. In unique setup of solar furnace at PROMES-CNRS in Od...
Repository :
Repositório do LNEG
Language(s) :
English
Fracture behaviour of a new submicron grained cemented carbide
Author(s) :
Oliveira, F. A. Costa
,
Lopes, A. C.
,
Fernandes, Jorge Cruz
,
Sacramento, J.
,
Valente, M. A.
Description :
In this work, the effect of increase argon pressure applied on a post-sintering treatment from MPa to MPa on the mechanical properties of a newly developed hardmetal grade, namely hardness, flexural strength and fracture toughness, is reported. The as-received material has been prviously sintered at...
Repository :
Repositório do LNEG
Language(s) :
English
(1S,2R,6R,7aS)-1,2,6-Trihydroxyhexahydro-1H-pyrrolizin-3-one
Description :
In the title compound, C7H11NO4, prepared via a Morita–Baylis–Hillman adduct, the five-membered ring bearing three O atoms approximates to a twisted conformation, whereas the other ring is close to an envelope, with a C atom in the flap position. The dihedral angle between their mean planes (all ato...
Repository :
Europe PubMed Central
Language(s) :
English
(1S,2S,6R,7aR)-2-Benzyl-1,6-dihydroxyhexahydropyrrolizin-3-one
Description :
In the title compound, C14H17NO3, the dihedral angles show that the H atoms at two stereocenters are in a trans-diaxial configuration. In the crystal, the molecules are linked by O—H⋯O hydrogen bonds. The absolute configuration of the molecule has been established on the basis of refinement of the H...
Repository :
Europe PubMed Central
Language(s) :
English
(1S,2E,6R,7aR)-1,6-Dihydroxy-2-(4-nitrobenzylidene)-2,3,5,6,7,7a-hexahydro-1H-pyrrolizin-3-one
Description :
The crystal structure of the title compound, C14H14N2O5, contains two distinct conformers in the asymmetric unit. The compound has three defined stereocenters, two of them contiguous, and a C=C double bond with an E conformation. The stereocenters exhibit the same chirality in both conformers, with ...
Repository :
Europe PubMed Central
Language(s) :
English
(1S,2E,6R,7aR)-2-Benzylidene-1,6-dihydroxy-2,3,5,6,7,7a-hexahydro-1H-pyrrolizin-3-one
Description :
In the title compound, C14H15NO3, the conformation of the double bond was determined to be E, confirming the result obtained from two-dimensional NMR data. The five-membered rings of the pyrrolizine unit exhibit C-envelope conformations, with C atoms displaced from the mean planes formed by the rema...
Repository :
Europe PubMed Central
Language(s) :
English
Efecto de la microestructura en el comportamiento tribológico de materiales monolíticos de Si3N4 y de compuestos Si3N4–SiC
Description :
The tribological behaviour of various Si3N4 based materials, including Si3N4/SiC composites, has been analysed from room temperature up to 700ºC, and for sliding speeds between 0.5 and 2 m/s. Materials have been prepared by hot pressing at 1750ºC in nitrogen atmosphere, varying α-Si3N4 phase content...
Repository :
DOAJ-Articles
Language(s) :
Spanish
Protein motors induced enhanced diffusion in intracellular transport
Description :
Diffusion of transported particles in the intracellular medium is described
by means of a generalized diffusion equation containing forces due to the
cytoskeleton network and to the protein motors. We find that the enhanced
diffusion observed in experiments depends on the nature of the force exert...
Repository :
arXiv
Language(s) :
Undetermined
Pattern formation and coexistence domains for a nonlocal population dynamics
Description :
In this communication we propose a most general equation to study pattern
formation for one-species population and their limit domains in systems of
length L. To accomplish this we include non-locality in the growth and
competition terms where the integral kernels are now depend on characteristic
...
Repository :
arXiv
Language(s) :
Undetermined
Newtonian Perturbations on Models with Matter Creation
Description :
Creation of Cold Dark Matter (CCDM) can macroscopically be described by a
negative pressure, and, therefore, the mechanism is capable to accelerate the
Universe, without the need of an additional dark energy component. In this
framework we discuss the evolution of perturbations by considering a
Ne...
Repository :
arXiv
Language(s) :
Undetermined